# Solved papers for 10th Class Science Solved Paper - Science-2015 Outside Delhi Set-II

### done Solved Paper - Science-2015 Outside Delhi Set-II

• question_answer1) Write the number of covalent bonds in the molecule of propane, ${{\mathbf{C}}_{\mathbf{3}}}{{\mathbf{H}}_{\mathbf{8}}}$.

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• question_answer2) Where is DNA found in a cell?

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• question_answer3) The first trophic level in a food chain is always a green plant. Why?

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• question_answer4) We often observe domestic waste decomposing in the bylanes of our homes. List four ways to make the residents aware that the improper disposal of wastes is harmful to the environment and also for their own health.

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• question_answer5) List any two advantages associated with water stored in the ground.

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• question_answer6)

 What is meant by homologous series of carbon compounds? Classify the following carbon compounds into two homologous series and name them. ${{\mathbf{C}}_{\mathbf{3}}}{{\mathbf{H}}_{\mathbf{4}}}\mathbf{, }{{\mathbf{C}}_{\mathbf{3}}}{{\mathbf{H}}_{\mathbf{6}}}\mathbf{, }{{\mathbf{C}}_{\mathbf{4}}}{{\mathbf{H}}_{\mathbf{6}}}\mathbf{, }{{\mathbf{C}}_{\mathbf{4}}}{{\mathbf{H}}_{\mathbf{8}}}\mathbf{, }{{\mathbf{C}}_{\mathbf{5}}}{{\mathbf{H}}_{\mathbf{8}}}\mathbf{, }{{\mathbf{C}}_{\mathbf{5}}}{{\mathbf{H}}_{\mathbf{10}}}$.

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• question_answer7)

 The elements $_{\mathbf{4}}\mathbf{Be}{{\mathbf{,}}_{\mathbf{12}}}\mathbf{Mg}$ and $_{\mathbf{20}}\mathbf{Ca,}$ each having two valence electrons in their valence shells, are in periods 2, 3 and 4 respectively of the modern periodic table. Answer the following questions associated with these elements, giving reason in each case: (a) In which group should they be? (b) Which one of them is least reactive? (c) Which one of them has the largest atomic size?

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• question_answer8) List three distinguish features between sexual and asexual types of reproduction, in tabular form.

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• question_answer9) List four points of significance of reproductive health in a society. Name any two areas related to reproductive health which have improved over the past 50 years in our country.

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• question_answer10)

 A pea plant with blue colour flower denoted by BB is cross-breed with a pea plant with white flower denoted by ww. (a) What is the expected colour of the flowers in their ${{\mathbf{F}}_{\mathbf{1}}}$ progeny? (b) What will be the percentage of plants bearing white flower in ${{\mathbf{F}}_{\mathbf{2}}}$ generation, when the flowers of ${{\mathbf{F}}_{\mathbf{1}}}$ plants were selfed? (c) State the expected ratio of the genotype BB and Bw in the ${{\mathbf{F}}_{\mathbf{2}}}$ progeny.

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• question_answer11) What is an ecosystem? List its two main components. We do not clean natural ponds or lakes but an aquarium needs to be cleaned regularly. Why is it so? Explain.

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• question_answer12) What are fossils? How are they formed? Describe in brief two methods of determining the age of fossils. State any one role of fossils in the study of the role of fossils in the study of the process of evolution.

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